teapandya wrote:
On Apr 18, 11:49 pm, DogMa wrote:
RuF wrote:
... Tea has NO tannic acid. Tea, not even the strong black Irish
Breakfast blend so beloved of trotting mice, will NOT tan leather,
Nigel at Teacraft
Since you are in the business, I question your statement.
Strichnyne is not poison because I sell it. :-)
Isn't cross-posting like this considered dubious netiquette?
However, I join the thread in both venues to put another vote of support
behind the Teacrafter.

As Lew, Rick and Scott point out, "tannin" is a pretty vague descriptor
with an etymology that long pre-dates anything like modern chemical
terminology. (An alembic of alkahest, anyone?) Where names like the
mouthful abbreviated in EGCG specify a precise molecular structure, many
(mostly so-called "trivial") names in common use specify nothing more
than similarity in only one or two properties out of dozens discernible.
Grease, for example, may derive from animal, vegetable or mineral or
combinations thereof; may commonly be a single phase of hydrocarbon, a
single or mixed monoester, triglyceride, cholesterol derivative or many
others; an aqueous emulsion; or a soap; all with or without additional
solid fillers like graphite or molybdenum disulfide, etc. etc. "All
grease is good for cooking"??

The problem is that, as in most disciplines, almost anyone can learn to
spell/pronounce the jargon and even use it with reasonable syntactic
precision without any real concept of underlying meaning. Nigel's a
seasoned professional *in this field*, as his diverse archived posts
make clear, and can be presumed to know what he's talking about. (I also
consider his probity to be beyond question, even though he's never sent
*me* any free samples.)

BTW, anent spelling, it's "strychnine" - from strychnos, one of
nightshades, a motley family indeed. Talk about bitter - makes caffeine
taste like honey.

-DM
(formerly in the business of designing, manufacturing and selling some
dandy poisons)

Dear Friends,
I have planted, grown, nurtured and made Tea for eighteen years and am
now into Blending and Packaging.
Does that make me a know all? No, it simply makes me want to know
more.
This group and its postings have given me an insight into many aspects
of my favourite beverage and my passion, and I would not discourage
the group to discuss any aspect concerning Tea.
But to doubt the credibility of members is simply not called for. I
have learnt from Nigel's posts. Those who wish to differ, and whats
wrong with it? Each one has a right to his opinion, and here is mine:-
One of the main virtues of Tea is that "... it does you no harm".
If it could indeed be used for tanning leather, the populace on the
plantations would not be in such a pitiable state. Can the claimants
of the presence of Tannic Acid in Tea let us know how to extract it
and use it, YES, for tanning leather. it will at least reduce the use
of some toxic chemicals in the leather industry, and perhaps provide
an alternative use for Tea Waste and fibre. There is a humane aspect
in this request, please do not ignore!
Regards,
Jayesh S Pandya.

Dictionaries and other reference books don't have the power to mold
the world to conform to the desires of us tea lovers. They have to
explain to people working with tannic acid every day such things as its
applications, which include, according to Merck 13 (entry #9141):

"Mordant in dyeing; manuf ink; sizing paper and silk; printing
fabrics; with gelatin and albumin for manuf of imitation horn and
tortoise shell; tanning; clarifying beer or wine; in photography; as
coagulant in rubber manuf; manuf gallic acid and pyrogallol; as reagent
in analytical chemistry.

"THERAP CAT: Astringent.

"THERAP CAT (VET): Astringent, hemostatic, in solutions for burns.
Has been used internally as an astringent and as a heavy metal antidote."

Leather tanning is a trade relegated to the lowly burakumin in Japan
(who also handle garbage and corpses) and is banished to districts far
downwind from human settlements in the Maghreb. I don't know much about
it except that it requires letting the skins of dead animals decay
somewhat before treating them with lye and tannic acid, and that it
smells very bad.

I doubt there's much tannic acid in tea, especially since the Merck
article contains a reference to a study of its toxicity and says in
italics, "Keep well closed and protected from light." It also says it's
"produced from Turkish or Chinese nutgall." So tea is obviously not the
preferred source of it.

(Incidentally, nutrition fans, it occurs in the bark of myrobalan.
Doesn't that ring a bell?)


--
Marshall Price of Miami
Known to Yahoo as d021317c